No offence, I like the idea, but I felt you should have worked on the overall finish, especially when working on commissions.
My advice to you would be to secure a deposit for commissions from now on and work on your finish. I personally never take on a commission without some form of commitment like 50% parts fee or half the parts themselves. At the end of the day, if I lose a client, they lose their money or stuff and I'm not as out of pocket as I would be as I can reuse the parts I have bought or have been given for other projects.